The present invention relates to insect control devices for livestock and to a process for protecting livestock against insects.
Livestock are frequently troubled by various types of insects such as flies and lice which transmit infection of the skin, eyes and ears as well as cause irritation leading to loss of production. Several approaches have been taken to alleviate this insect problem. One approach requires application of an insecticide spray on the animal. This approach is undesirable because it requires a substantial amount of time and labor to gather the animals to be treated and then to treat the animals. Further, application by this method is effective for only a short period of time so that frequent applications are necessary to effectively treat the livestock. A more economical and less labor intensive approach is therefore generally preferred.
One approach which is used is application of insecticide by having the animal to be treated come into contact with a device from which the selected insecticide is dispensed. Dispensers such as dust bags or oilers are placed in areas where it is anticipated that the livestock will come into contact with them. This approach does reduce the amount of labor involved in treating livestock, but it does not ensure that each animal will receive the necessary treatment at regular intervals.
Another approach employs slow release pesticide technology. In this approach, a pesticide is mixed with a resinous substance which will release the insecticide over an extended period of time. These pesticide containing resins have been used in a variety of forms ranging from collars to tags which should be attached to various body parts of the animal. The use of pesticide containing ear tags is of particular interest for treating livestock as is evident from the large number of publications and patents directed to such ear tags.
For example, U S. Pat. Nos. 4,366,777 and 4,562,794 each disclose ear tags in which a liquid insecticide dispenser is used. In U.S. Pat. No. 4,366,777 the insecticidal liquid which is enclosed in a fibrous or foam reservoir is wicked onto the surface of the tag to provide insecticidal activity. In U.S. Pat. No. 4,562,794, the dispenser or reservoir containing the insecticide is attached to an animal identification tag. Release of the insecticide is dependent upon migration or diffusion of the insecticide through a semipermeable membrane.
U.S. Pat. No. 4,428,327 discloses an insecticide impregnated tape which is attached to a conventional ear tag. Each of these tags has been found to be disadvantageous because the insecticide containing reservoir or tape may be detached from the tag on fences or brush. It would therefore be advantageous to have a tag in which the insecticide is directly incorporated.
Such an approach is disclosed in U.S. Pat. Nos. 4,721,064, 4,195,075 and 4,265,876 as well as in Miller et al, "Release of Pyrethroids from Insecticidal Ear Tags", J. Econ. Entomol. 76:1335-1340 (1983) and Miller et al, "Release Rates From Cattle Insecticidal Ear Tags In Various Regions Of The United States", The Southwestern Entomologist, Vol. 11 No.1, pages 45-50 (March 1986). The Miller et al disclosures and U.S. Pat. No. 4,195,075 are, however, limited to use of liquid insecticides which will evaporate at ambient temperatures. Use of such liquids may be undesirable in areas where the ambient temperature is high enough to cause rapid evaporation of the insecticide and thus result in an undesirably greater release of insecticide over a shorter period of time.
U.S. Pat. No. 4,721,064 teaches that any of the well known migratory and/or vaporizable insecticides may be incorporated in the disclosed tags. Coumaphos is not, however, a migratory or vaporizable insecticide.
U.S. Pat. No. 4,265,876 is limited to tags containing pyrethroid insecticides whereas coumaphos is not a pyrethroid.